This invention relates generally to an improved electrical connector for connecting first and second conductors. More particularly, but not by way of limitation, this invention relates to an improved electrical connector that is particularly suited for use in connecting first and second conductors in a remote location in the presence of an electrically conductive environment.
In the logging of oil and gas wells and the like during the process of drilling the well, electronic sensing devices of various types have been located in the drilling string which supports the drill bit used for forming the well bore. The electronic sensors sometimes include means for transmitting the signal up a conductor installed in the drill string or transmitting a signal through the mud system used for lubricating and cooling the bit. In other instances, the electronic sensor has included a memory onto which the data or information sensed by the sensor is recorded. In these instances, the practice has been in the past to recover the sensor and the recorded data by pulling the drill string from the well bore either for that purpose or on the occasion of changing a worn drill bit.
As mentioned above, it has been necessary in the past to pull the drill string from the well in order to obtain the contents of the sensor's memory. Such a procedure is involved, expends a substantial amount of time and effort, and is expensive in terms of lost drilling time. If the memory is not queried except when the drill bit is worn and must be removed from the well, the data recorded is not obtained when desired and thus does not fulfill the ultimate aim of obtaining the information related to the well bore at the earliest possible time after recording.
In an effort to alleviate the foregoing difficulties, it has been proposed to mount the electronic sensing device having a memory in the drill string slightly above the bit. An electrical conductor will then be extended into the well bore, that is, through the drill pipe, and a connection made with the sensor which will provide means for querying the sensor's memory without the necessity for removing the drill string from the well bore.
To further complicate the problem of obtaining the data from the recorder (memory) located in the drill string, it is highly desirable, even if drilling of the well is stopped, to continue circulating "drilling mud" down the interior of the drill pipe and up the annulus between the drill pipe and the well bore wall. Stopping the mud flow for long periods may result in caving of the walls of the well bore and the sticking of the drill pipe therein. Therefore, it is desirable, if not necessary, to continue to circulate the drilling mud through the drill string and upwardly through the annulus as the recorded data is obtained from the sensor.
With the continued circulation of the mud, the remote location of the sensor, extremely high hydrostatic pressures, elevated temperature, the presence of solids, sand, and the conductivity, high viscosity, etc. of the mud, it will be appreciated that difficulty in making a connection with the sensor that is adequate for the transmission of data will be encountered. Manifestly, such a connection must be electrically sufficient so that the data can be transmitted at high frequency therethrough, and yet, must be a connection that can be easily and positively released by pulling up on the conductor even though the sensing device may be located as deep as 20,000 feet or more in the well bore.
As the drilling mud flows through the drill pipe, and due to the nature of the mud pumps utilized for circulating the drilling mud, some surging occurs which causes the conductor to be somewhat unstable as it is lowered into the drill pipe. Even if and after a connection is made, there is a possibility of movement between connector parts in the connection which, when attempting to transmit data, may cause line noises that interfere with or destroy the data transmission. For example, if a mechanical pin is inserted into a socket that has spring loaded contacts, the slight movement of the pin relative to the contacts may generate high frequency noises that are imposed on any signal transmitted over the conductor. Accordingly, it is highly desirable to provide a connector which eliminates the cause of such noises.
An additional difficulty, which has previously been touched on, in constructing a connector for use in well bores is that more often than not, the drilling mud is saline and thus is a conductor. The connector for use in a system used in well bores then must exclude the presence of the conductive drilling mud in order to be able to accurately transmit the data from the sensor.
It is an object of this invention to provide an improved electrical connector that would meet the above criteria. It is a further object of this invention to provide an improved electrical connector that will provide noise-free electrical connection between conductors in a harsh environment which may include liquids at pressures that may be 20,000 psi or higher, temperatures that may be 400.degree. F. or higher, and may contain abrasives flowing at high velocities.